Embryonal Rhabdomyosarcoma in Middle Ear: A Rare Case Report

Abstract

Rhabdomyosarcoma (RMS) in middle ear and mastoid are uncommon. Presentation of RMS in these sites include purulent or blood stained discharge, polypoidal mass and granulation tissue. Clinical diagnosis may be delayed due to similar presentation as Chronic Suppurative Otitis Media (CSOM). Authors herein report a case of six-year-old male patient, who presented with a blood stained discharge from right ear for 15 days. On otoscopic examination, a polypoidal mass in external auditory canal was identified. A history of ruptured right tympanic membrane with occasional discharge for two years had been given. Clinical diagnosis of CSOM with aural polyp had been made. Radiographically, it was a soft tissue lesion with poorly defined margins. There were no bony erosions with minimal collection in right middle ear cavity. On routine histopathological examination diagnosis of round cell tumour had been made. On Immunohistochemistry (IHC), tumour was immunoreactive for desmin and vimentin, while negative for Cytokeratin (CK), Leukocyte Common Antigen (LCA), chromogranin and synaptophysin. Tumour was diagnosed as RMS (Embryonal type). This case report shows importance of early diagnosis of RMS in middle ear, which is often delayed and misdiagnosed as CSOM. Delayed diagnosis may lead to, facial nerve involvement, local meningeal involvement and distant metastasis. Histopathological examination and IHC e.g., desmin positivity are the mainstay of diagnosis.